The Mitsubishi Pajero Owners Club®

[assassin]

Replacing brake back plates is a common job and unfortunately it is a time consuming job which many people think is beyond them and with a little knowledge and basic fabrication skills many people can undertake basic repairs to their back plates to prolong their life as usually it is just the flanges which rot and not the centres which hold the hand brake shoes.

For the purposes of this article I will use the MK IIII Shogun as the front discs rotors and rear disc rotors are 332mm diameter and you can make one jig to make repair sections and for other models you can follow the same process and make repair sections based upon your disc rotor diameter.

To begin you need to make your jig and for this you get replacement disc rotors and use one of your old ones and you clean it up ready for welding, you need 25 X 6mm steel strap and you bend this around your rotor and weld it as you go, this gives you a round jig of 344mm diameter.

To make your repair section you take a sheet of steel of whatever thickness you like; I prefer 2mm but you can use ordinary 1.2mm body steel of you like and you cut an inner hole and the outside round and in our example the dimensions are 368mm outside diameter and an inside hole of 228mm. You mark these with engineers dividers which are basically a large compass made from steel with a sharpened point and you centre pop your plate and mark from there, the sharpened point scribes your steel and gives you an accurate line for both inner and outer cuts and you use a large hole saw to make your inner hole cut start and gently cut it out. Cut your outer diameter and you are left with a flat steel disc which you put on your jig, line it up accurately so you have a 12mm overhang all around and firmly clamp the steel disc to your new jig and gently work around it with a hammer and hammer the steel around your jig to give you a 12mm flange all the way round, you now have the repair section and make as many as you need.

Strip your brakes down and remove your calipers and the carriers; the discs and on the rear, the handbrake shoes so you are back to the back plate and you thoroughly clean them with brake cleaner and let it evaporate, if you have an angle grinder fit a stainless steel bristled wire brush.  Always use goggles for the next stage as the bristles fly off ant over 300 MPH and you don’t want a stainless steel bristle in your eye, grind all rust off with your grinder mounted wire brush until the remaining back plate is spotless and free of rust, you can use a drill with a drill mounted abrasive if you don’t have an angle grinder.

Paint the inside and outside of your backplate with epoxy paint primer and let it harden and apply a second coat so it is fully covered and coat your new repair sections and let the lot cure for the recommended period or overnight, Take your new repair section and put it in a vice and carefully clamp and slit through one side with a hacksaw and note your original backplates have a slot in them for the caliper to fit so feed the new repair section in starting from the cut out and this should slide neatly over the existing backplate and its original flange, if it doesn’t and they rarely do, you have to adjust the original backplate with a small hammer. When it fits neatly you can loosely fit your new brake rotor and check it has an equal gap all around it and once you are happy with the fit you mark the inside of the inner hole which should give you 25mm of overlap on the existing backplate and you mix some epoxy resin glue and apply to your marked lines and pull your repair section back and clamp it until the epoxy has cured. Leave the clamps on next to your cut out for the caliper and gently cut your backplate with a small hacksaw and clean with a file so there are no sharp edges. Paint the entire backplate with the colour of your choice; I would suggest black as the original colour was black and mask off any areas not requiring painting and once dried you can rebuild your brakes safe in the knowledge your backplates are sound.

Can you do this with any size brake backplate? Yes as you simply form the steel strap around the backplate and allow 12mm all around to form the flange and leave 24/25mm to contact the rear of the backplate to adhere to with epoxy; take note of any fittings such as bleed nipples or fixing bolts and any hydraulic pipes. You can make these for any car by simply having the old brake rotors and some 25 X 6mm steel strap and a welder to make the jig.

[Google]